Instead of putting the onus on you to choose the best keyword, just-launched semantic search engine Powerset can find the answers you seek on the Wikipedia using natural language. Type things like "what is a life hack" or "paintings by Salvador Dali" and Powerset extracts those answers from Wikipedia and lays them out on an attractive page. CNET reports:

Powerset's natural language search technology is based on patents licensed exclusively from PARC and its own proprietary indexing. Powerset's engine has read 2.5 million Wikipedia pages and extracted "meaning" from the sentences, creating a navigation and semantic layer on top of the popular Web encyclopedia.

In my tests, Powerset was slow to respond (no doubt suffering from launch overload), but you can check out a video of Powerset in action after the jump.